<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{padding:0; margin:0;}
        a{
            text-decoration: none;
        }
        li{
            list-style: none;
        }
        ul{
            width: 527px;
            height: 44px;
            border-bottom:1px solid #bebebe;
            margin: 100px;
        }
        ul li{
            float:left;
        }
        ul li a{
            /* 最终改的是a标签 */
            width:88px; height:38px; border: solid 1px #dadada;
            
            background: #f7f7f7;
            display: block;
            margin-top:5px; margin-left:10px;
            color: #a2a2b5;
            text-align: center;
            line-height: 38px;
        }
        ul li a:hover{
            /* 最终改的是a标签 */
            width:88px; height:44px;  
            border:1px solid #bebebe;
            border-bottom: none;
            margin-top: 0;
            background: #fff;
        }
    </style>
</head>
<body>
   <ul>
       <li><a href="#">tab one</a></li>
       <li><a href="#" >tab one</a></li>
       <li><a href="#">tab one</a></li>
       <li><a href="#">tab one</a></li>
   </ul> 
</body>
</html>